Prioritizing purchases: IS A SUMP NECESSARY? WHAT CAN IT DO?

[Sk8r]

From the start: to sump or not to sump, and what choices do I have?
1. Sump with downflow if you have ANY remote suspicion you want to go reef...it will be extra gallons of water volume; it provides food if it has a fuge; it serves as a backup sandbed if you have a rock/sand/cheato fuge; it provides a place where you can put your skimmer besides full view in your living room. Yes, you COULD do a 'shroom or button reef with a cannister, but read on: The big deal is that skimmer. When you get into stony coral, a skimmer is pretty well a must-have. And when you get into the fussier stony, a really good skimmer is a must.
Fish-onlies can get by nicely skimmerless on a monster canister, ---we have a canister the size of an office wastecan that runs our freshwater 50 gal, and I'm sure this would handle a salt fish-only very nicely; but there's no reason a fish-only can't use a sump and fuge in place of a large cannister, and that turns them into a FOWLR (fish-only-with-live-rock), which is pretty well everything a reef is except the corals: live rock, live sand, with a sump---this works if your live rock is sufficient to carry your whole fish load without nitrate problems. The FOWLR is the addition of one lone mushroom away from being a reef, and since I've never found any fish that eats mushrooms, it might be something to explore. Mushrooms are colorful, prolific, and are VERY good water quality indicators: if they tuck up and wrinkle, you have an alkalinity problem that needs urgent attention! I find a shroom reef FAR easier because the shrooms fairly well tell you things are good or they aren't. Plus---they eat fish waste: they're living filters. So if you can keep your fish load down so the shrooms don't get overwhelmed chemically by waste---you can strike a very happy balance. You can also do this with a cannister: our tanks got along this way back in the Jurassic and the fish/shroom tank can do nicely for a beginner. Just don't go for the 'designer shrooms' for your first try. Stick to discosomas, the hard greenstripes and purples and browns that are smooth, not fuzzy. These are so tough they could survive a cycle, and they're a very good first tank. Be warned: if they take up residence on a rock, you have a mushroom rock, and you'll have a time getting them off it, because they reproduce from fragments. When I've had them, I've just watched WHAT rock I let them take, and have traded such rocks as 'specimen' rocks...one of them 8"x8" and absolutely frilly with green striped ones.

I personally recommend a skimmer as soon as you commit to a sump: if you see what sort of nastiness mine pulls from water I don't rate as particularly 'fine' you'd be appalled---it's like the tank's sewer. It does what the surf does for the ocean: create a foam that, when it melts, becomes green-brown oozey stuff. I remember reefing when we DIDN'T have this technology, and while I know you can do it---because we did---there were things we couldn't keep that now thrive in our tanks.

One reason for having a sump is a place to put a skimmer and other reactors so they won't leak on your carpet. A sump can also provide live food for your tank if you have a sump/fuge. I set my skimmer up on a shelf to drop water into my tank so I had that middle chamber free for a fuge (algae farm) and still know that skimmer can't leak except right down into the sump. It lets you do supplement additions without dumping stuff straight into your tank where your critters are: helps it mix better before it gets to them.
And it's a good place to put that hairy little crab you caught and haven't the heart to kill. A critter that would wreak havoc above can have a happy life in your fuge or sump.